User:Tsunko/TechInfo

"How does this game communicate!?"

Generally, communication is done over plain HTTP. Headers (as far as I can tell) are not used; I could be wrong on that fact, but I have no observed anything weird happening if I don't include certain headers.
Any encryption done uses AES128 ECB with a block and key size of 128, padding data with zeros, followed by being the encrypted result being represented in Base64. Data is contained in JSON objects (typically, all data is wrapped inside of a named JSON object for some reason).

Client to Server

Oddly enough, client to server isn't fully encrypted at all. If there is any encryption present, it is only done to any strings being passed from client to server. Other than that, expect plaintext.

Server to Client

Data transmitted from the server is fully encrypted, however, unlike the client to server, there is no "nested" encryption. The client expects everything to be plaintext once the content is decrypted the first time.

The infamous brick wall we can't break.

This file (on Android) is stored under /data/data/jp.co.nexon.kemo/files/kemofure/resources/common/common/data0.bytes.
It's loaded before either the client attempting to view the tutorial or view /mypage/get by class MasterData.cs.
The heart-breaking part is that it is encrypted with Rijndael-256 with a block and key size of 256, making it practically impossible to recover the key. The default keys (appDecryptionKey/UtilData.AES_KEY) provided (QeEjSWTbFK2876yB or b8PWNMsYCt47YAai) do not work with this file; it's encrypted with a different key. However, we at least know the IV (FLXR4JXfD6Cw5jsJtj7VnferY93k4Zsg).

"I have the key!"

Should you, or anyone else, happen to have or stumble across the decryption key (either you sniffed it or somehow logged the HTTP request), please contact me on Discord.

"I want to help find the key!"

Unfortunately, while the Servals working in Nexon's programming department may have some of the most convoluted code possible (we'll call it a unique style of code), it does not look like finding the key will be something you randomly stumble across. However, here are some ways to try finding them:

1. The most likely way to find it (and how I've been doing it) is to simply download other Nexon mobile games into an emulator with ProxyDroid setup to redirect traffic to a Fiddler instance. Look for any "startup" HTTP requests and see if they have a key. If they do, tell me them on Discord.
2. Downloading APKs of any Nexon mobile games and decompiling them, inspecting any classes that could contain keys. Essentially, you're looking for any class that has the word "Crypto" in it, but the key could be hiding in other classes.
3. Seeking assistance from others that could potentially have the key. This is probably the 2nd least likely, as they're probably not going to share the key (this is something that's probably sought after by many other developers). The most promising people who might have such key (or at least a decrypted copy of the data) are anons running around on the Gamerch wiki with the ID CB26BC965F and CFF60E1F35.
4. Dressing up in a suit and walking on over to Shinkawa 2-3-1 Chuo-ku, Tokyo 104-0033 Japan, politely asking for the decryption key. We've tried getting Bird and Shadow on this, but they've declined :(

"Let's recreate the file!"

... is our current best bet. The syntax of the file is relatively simple: [number of elements]>[JSON elements] The structure of the file has been documented (this is also the same order things are loaded in, and yes, it is fixed ordering):

Data Types

Type	Actual type
i	32-bit integer
l	64-bit integer
f	decimal floating; probably 32-bit floating?
s	string of characters
a	array of elements; the element is typically a JSON object, which will be described in comments.

MstLevel

Field Name	Type	Comment
level	i	internal ID
exp	i	possible EXP rewarded at end of level?
maxStamina	i	possible stamina required? not too sure.

MstItem

Field Name	Type	Comment
id	i	internal ID
name	s	Name of the item
info	s	Description of the item
unit	i	??? unsure
itemType	i	internal ID referencing the type
itemTypeValue	i	unsure what it references
possessionLimitCount	i	maximum amount that can be inside inventory
effectRarity (optional)	i	internal ID referencing the rarity of the item (possibly just visual) (default: 1) (1-6?)
sortNo (optional)	i	possible sorting index for when viewing (i.e item with sortNo 1 would be first, 2 would be second etc) (default: 1)

MstCharacter

Field Name	Type	Comment
id	i	internal ID
name	s	Name of the character
rarity	i	rarity value (knowing typical gatcha, from between minimum of 1 to maximum of 6)
maxLevel	i	highest level possible with character
hp	i	base hitpoints?
maxHp	i	hitpoints when fully grinded out?
attackType	i	internal ID referencing the type of attack done (enum index number possibly)
attack	i	default amount of damage?
maxAttack	i	maximum amount of damage?
moveSpeed	i	movement speed of the character (unsure of what range though)
attackSpeed	f	attack speed of character (? my guess is 1.0 would mean 1 attack a second)
attackRange	i	the attack range/reach of the character
reach	i	melee reach? unknown, really
weight	i	how many japari buns does this character eat :^)
knockBack	i	units to move attacked unit back?
sameAttackCount	i	unknown, possible how many times the character can repeat a single attack
attribute	i	attribute of character (cool, beauty, whatever else was TL'd from that attribute array)
groupId	i	group id of the character (not sure
skillId	i	unsure, maybe the internal power skill ID the character has?
skillChargeSpeed	f	unsure, since it's a float, i'd assume "1" is fully charged and "0" is no charge
readerSkillId	i	unsure, don't know what a reader is
skillSE	i	skill sound effect index?
cost	i	cost to summon unit
limitBreakStatus	a	no clue maxLevel i maximum limit breaks maxHp i unknown, what would hp would have to do with limit breaks? maxAttack i unknown
goodField	i	field type that is beneficiel for the character
badField	i	field type that is detrimental for the character
nocturnal	i	unknown, possible time-related (owls do more damage at night or something? i wouldn't have a clue)
critical	f	crit chance
baseCharacterId	i	internal base character ID, possibly for when characters evolve or have multiple rarities
profile	s	description?
scientificName	s	name of the character in scientific terms (i.e Suri Alpaca is "Vicugna pacos")
genus	s	the genus of the character (i.e Suri Alpaca is "Vicugna")
redlistCode	i	conversation status?
word	s	???
voiceArtist	s	seiyuu
size	i	size of the character (S, M, L)
specificVirtue	a	??? mstEventId i ??? mstSpecificVirtue i ???
maxLimitBreakReducePercent (optional)	i	??? (default: 0)
effectRarity (optional)	i	rarity of the character's special effect? unsure. (default: 1) (1-6?)
eventLimitBreakFlag (optional)	i	unknown (default: 0)
tieUpFlag (optional)	i	unknown; also... :2lewd: (default: 0)

MstCharacterRarity

Field Name	Type	Comment
rarity	i	rarity of a character? (1-6)
salePrice	i	possibly how much they cost?
dropPercent	i	chance to get character
maxLimitBreakCount	i	maximum amount of times the character can be limit broken
stockExp	i	amount of xp when obtained? (default: based on rarity, can be: 0, 500, 1000, 2000, 5000, 10000)
maxLimitBreakReduceCoin	i	??? (default: based on rarity, can be 0, 0, 0, 30, 100, 300)

MstLevelCharacter

Field Name	Type	Comment
characterLevelList	a	possibly referencing data per level (how much to get to this level, etc) level i not much to say; it's the level exp i exp required? limitBreakStep i ???

MstUpGrade

I actually don't know what this is used for.

Field Name	Type	Comment
level	i	???
cost	f	???
hp	f	???
attack	f	???
knockback	f	???
weight	f	???
hpRecover	f	???

MstKemonoLevelUp

Field Name	Type	Comment
getUp	f	??
recoverSpeed	f	??? how fast to recover per second? or something?
needKp	i	?? unknown

MstGroup

Field Name	Type	Comment
id	i	internal group id
name	s	name of group
information	s	possibly description or profile
effectValues	s	a string of integers, seperated by commas (i.e "1, 2, 3, 4, 5")
members	s	a string of members, seperated by commas (i.e "a, b, c")
prefixString	s	prefix for the group for its members
suffixString	s	suffix for the group for its members
effectInformation	s	possibly information regarding how the effect values work; could be informational and not do anything

MstSkill

imagine combining 6 friend attacks all at once :wao: (ty Chojiki for explaining how it worked)

Field Name	Type	Comment
id	i	internal skill id
name	s	name of the skill
info	s	display information for skill?
prefixString	s	prefix for skill name
middleString	s	the skill name itself
suffixString	s	suffix for skill name
skillEffectId	s	comma seperated string of integers (i.e "1, 2, 3, 4")
skillChrageSpeed (optional)	f	speed at which the skill charges (default 4f)
skillSE (optional)	i	skill sound effect index? (default 0)
skillWaitingTime (optional)	i	how long to wait before recharge (milliseconds?) (default 3000)
resourceId (optional)	i	internal id for visual effects? (default 0)
skillStartUpCondType (optional)	i	conditions for getting the skill pulled off? (default 0)

MstAccessory

Field Name	Type	Comment
id	i	internal id for accessory
name	s	name of the accessory
information	s	flavor text
useCondType	i	ID for condition type in which this accessory can be equipped? (maybe restricted to type?)
useCond	i	ID for condition?
effectType	i	??
effectValue	i	??
salePrice	i	the value of the accessory in, maybe, gold?
effectRarity (optional)	i	special effect for rarity (default 1)

BusLevelList

No clue what this does

Field Name	Type	Comment
type	i	???
level	i	???
gold	i	???
defaultKp	i	???
hp	f	???
attack	f	???
addKp	f	???

MstBusParts

could possible be related to MstItem?

Field Name	Type	Comment
id	i	internal id referring to the bus part
name	s	name of the part
info	s	flavor text?
type	i	type of part?
useCondType	i	??
useCond	i	??
effectType	i	??
effectValue	i	??

MstLogin

Field Name	Type	Comment
count	i	how many times to login to recieve reward
rewardList	a	rewards at x amount of logins type i type of award typeValue i ??? value of type? amount i the amount recieved

MstCostume

suri alpaca in shoebill costume??? ehehe...

Field Name	Type	Comment
id	i	id for costume
name	s	name of the costume
info	s	flavor text
effectType	i	???
salePrice	i	gold value of costume??
colorVariation	s	flavor text variation?
effectRarity (optional)	i	rarity special effect for item (default 1)
displayGroup (optional)	i	??? (default 1)
useCondSize (optional)	i	i guess certain friends can't wear certain costumes based on size (default 0)

MstCharacterStoryQuest

Field Name	Type	Comment
id	i	id for the story quest
name	s	string name for quest
stamina	i	stamina required?
fieldId	i	the field type for this quest
night	i	ah, this makes the "nocternal" field make sense; probably 0 for false, 1 for true; makes the field night-time
waveCount	i	amount of waves
linkMapId	i	next quest point on the map?
linkAreaId	i	next quest point in the area?
linkSymbolId	i	???
nextIds	s	no idea how this is formatted
rewardItemId	i	the ID of the item rewarded at the end of the quest
startAdvCharaId (optional)	s	???
endAdvCharaId (optional)	s	???
chapterSubtitle (optional)	s	???
episodeSubtitle (optional)	s	???

MstLevelMission

Field Name	Type	Comment
id	i	id for the mission
name	s	string name for mission
information	s	flavor text
nextMissionId	i	the next sequential mission ID

MstBus

Field Name	Type	Comment
id	i	id of bus
name	s	name of bus
information	s	flavor text
useCondType	i	condition type
useCond	i	condition
effectType	i	effect type ID
effectValue	i	value of the effect ID
itemId	i	???
groupId	i	???

MstSpecificVirtue

Field Name	Type	Comment
id	i	internal id for virtue
type	i	type of virtue
value	i	value of virtue
targetId	i	???
resourceId	i	target resource ID

MstArea

I can't figure out how this works exactly. The code is confusing.

Field Name	Type	Comment
id	i	ID for the area
name	s	Name of the area

MstQuestArea

might be bugged? this doesn't take input json data

MstQuestSymbol

Field Name	Type	Comment
id	i	id for the symbol
type	i	type of symbol
iconId	i	the internal resource ID for the icon
x	i	possibly X offset?
y	i	possibly Y offset?

MstEvent

All fields are optional in this.

Field Name	Type	Comment
id	i	id for the event
type	i	type of event
name	i	name for the event
countMstItemId	i	how many item IDs are involved
informationUrl	i	??? maybe URL for additional information about the event

MstCampaignQuestNotice

switch (this.NoticeType) case 1: this._APService = true; this._RaidUp = false; this._Guerrilla = false; break; case 2: this._APService = false; this._RaidUp = true; this._Guerrilla = false; break; case 3: this._APService = true; this._RaidUp = true; this._Guerrilla = false; break; case 4: this._APService = false; this._RaidUp = false; this._Guerrilla = true; break; case 5: this._APService = true; this._RaidUp = false; this._Guerrilla = true; break; case 6: this._APService = false; this._RaidUp = true; this._Guerrilla = true; break; case 7: this._APService = true; this._RaidUp = true; this._Guerrilla = true; break; All fields are optional in this.

Field Name	Type	Comment
id	i	id for the notice (default 0)
noticeType	i	type of notice (default 0)
displayImageName	s	path to image for notice? (default empty string)
startDatetime	l	when the quest starts? (unix epoch time probably) (default 0, or January 1st, 1970, 00:00:00)
endDatetime	l	when the quest ends? (unix epoch time) (default 0, or January 1st, 1970, 00:00:00)

MstSerif

font?

Field Name	Type	Comment
id	i	id for the serif
type	i	type of font?
mstCharacterId	i	???
displaySeq	i	??
editType	i	??
serif	s	??